net: tls: fix returned read length with async decrypt

jira VULN-136507
cve-pre CVE-2025-39682
commit-author Jakub Kicinski <kuba@kernel.org>
commit ac437a5

We double count async, non-zc rx data. The previous fix was
lucky because if we fully zc async_copy_bytes is 0 so we add 0.
Decrypted already has all the bytes we handled, in all cases.
We don't have to adjust anything, delete the erroneous line.

Fixes: 4d42cd6 ("tls: rx: fix return value for async crypto")
Co-developed-by: Sabrina Dubroca <sd@queasysnail.net>
	Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
	Signed-off-by: Jakub Kicinski <kuba@kernel.org>
	Reviewed-by: Simon Horman <horms@kernel.org>
	Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit ac437a5)
	Signed-off-by: Brett Mastbergen <bmastbergen@ciq.com>

Author: bmastbergen

net/tls/tls_sw.c

@@ -2111,7 +2111,6 @@ int tls_sw_recvmsg(struct sock *sk,
 		else
 			err = process_rx_list(ctx, msg, &control, 0,
 					      async_copy_bytes, is_peek);
-		decrypted += max(err, 0);
 	}
 
 	copied += decrypted;